The invention relates to a spreading device for treatment of hip dysplasties, which device retains the patient's legs in a spread-out condition to retain the parts of the hip in proper relationship.
Hip dysplasties or dysplasties of the hip joints or thigh joints which can be subjected to treatment by means of such devices occur rather frequently with newborn babies. Such dysplasties usually involve too steep a formation of the roof of the socket of the coxa and a discoloration of the globular head of the femur from the center of the socket, without necessarily also presenting luxation or subluxation. Such ill formed hip joints must be subjected to a kind of treatment which will orient the globular head of the femur to the center of the socket and exert axial stimulating pressure to promote the formation of the ball and socket joint. This can be achieved by putting the legs into a spread-out position at which the globular head automatically will be oriented downwards to the center of the socket of the coxa because of the engaging muscles. Treatment by means of a spreading device usually is initiated at an early infant age before the child begins to stand up and walk. It is important that the spreading device should not unduly restrict the child's movements in order not to inhibit the development of the muscles.
In a known spreading device of this kind, back support and side portions are associated with a pelvis basket which has openings for the thighs and the front of which is constituted by a spreader bar with an upwardly directed projection connected by securing means in the area of its top end with the two side portions above the thigh openings. Thigh splints, which are like leaf springs, are each pivotally supported at a side portion above the thigh openings, and in a rest position they enclose an angle of 30.degree. to 40.degree. with the sagittal plane or plane of symmetry of the pelvis basket. Thus, each thigh splint extends parallel to the associated thigh at the outer side thereof. The supporting dishes are mounted at the thigh splints for adjustment in longitudinal direction of the splints and each comprises a belt embracing the thigh.
With such a known spreading device the desired achievement and success of the treatment cannot be obtained unless the following conditions are observed:
(a) The pelvis basket must be applied firmly to the child by a hip belt and by tightening the above-described securing means between the upwardly directed projection of the spreading bar and the two side portions so that the child cannot become displaced laterally in the pelvis basket. Otherwise, the child might adopt a position at which the required spreading is guaranteed for one thigh only, whereas the other thigh could return almost to normal position.
(b) The supporting dishes must be so adjusted that they exactly reach the hams or knee hollows, and the corresponding belts must be placed tightly around the thighs. Otherwise the child might attempt to close the thighs and thus press the globular heads of both hip joints outwardly again towards the upper edge of the socket thereby causing a mechanical load distribution which is unfavorable for the success of the treatment. Usually the infant patient finds these conditions annoying after a short while so that he is tempted to get rid of at least part of the belts surrounding his thighs and body, and larger children soon are successful in thus freeing themselves. This presents another hazard for successful treatment.
The known pelvis basket also is an obstacle to the proper personal hygiene of the child.
It is, therefore, an object of the invention to provide an improved spreading device of this type which will guarantee that both a spread-out position and stressing of the thighs which are favorable for successful treatment are maintained while, at the same time, obstructing and annoying the patient as little as possible.
It is another object of the invention to provide such a spreading device which is uncomplicated and easy to install.
It is a further object of the invention to provide such a spreading device that promotes personal hygiene of the patient.
It is yet another object of the invention to provide such a spreading device which an infant patient cannot remove.
These objects are met, in accordance with the invention, in that the thigh splints are joined to the associated side portions by arches, each of which extend forwardly towards the inside and is to be applied to the patient between the pelvis and the thigh. The thigh splints are to be applied diagonally to the inner sides of the thighs, from the top in front to the bottom towards the rear. The spreading device is designed as a spreading brace of the general nature of a leaf spring, leaving free the zone of the patient's perineum and rump.
This makes it possible for a forwardly directed supporting force to act on the sacrum and, furthermore, for pressure from above to be exerted on the femoral neck areas and pressure from below to be exerted simultaneously on the thighs in the area of the hams, while the legs are in spread-off or spread-out position. Thereby, the globular head of the femur of each coxa is oriented towards the center of the corresponding socket without the use of any belt tightened around the thigh or body. As the design of the spreading braces according to the invention is such as to resemble a leaf spring, the three points of support defined above are interconnected flexibly so that the required corrective pressure is exerted at each of them, with the patient in any position. The infant patient is uncovered at body parts which may become dirty, and he can wear any of the commercially available diaper panties. Furthermore, he is also free to make any movements corresponding to his age without risking a displacement of the spreading braces which would endanger the success of the treatment.
Preferably the spreading brace in accordance with the invention is formed integrally of plastics, various copolymers having proved to be especially well suited.
In a preferred embodiment of the invention the longitudinal axes of the thigh splints, in relaxed condition, lie at least approximately in a common plane at right angles to the plane of symmetry of the spreading device.
The spreading braces thus formed according to the invention are applied to the patient from behind so that the back support will abut in the area of the sacrum. From that area the two side portions extend into the areas of the thighs, and each arch joined to the side portions extends between the pelvis and the thigh to the front side of the thigh. Then the corresponding thigh splint extends across the front and inner sides of the thigh, diagonally into the ham, where the lower part of the thigh is embraced by the associated supporting dish upon having introduced the thigh from behind into the supporting dish by lever action. The child thus is unable to strip off the spreading brace according to the invention without any help from outside.